In order to diagnose breast cancer, breast biopsies are performed. Various types of breast biopsy exist such as fine needle aspiration (FNA), core needle biopsy (CNB) which can be performed under ultrasound or under X-ray guidance (stereotactic biopsy), vacuum-assisted biopsy (VAB), incisional biopsy (IB) or an excisional biopsy (EB). In a FNA a thin needle is used to harvest a small amount of cells for cytological inspection. In a core needle biopsy typically a 16 or 14 gauge biopsy needle is used to obtain a tissue specimen that allows histological investigation. Typically more than one biopsy is taken per procedure in order to obtain sufficient tissue that allows staging of the tumor (in situ versus invasive). Since more than one biopsy is taken, multiple needle insertions are required. VAB is similar to CNB with the difference that tissue in sucked into the device such that multiple biopsy samples can be harvested with only one needle insertion. The IB and EB are invasive surgical procedures in which a surgeon uses a scalpel to cut through the skin to remove either a piece (IB) or the complete lesion including some margin (EB). This last procedure is in fact a lumpectomy.
In the case of VAB multiple biopsies can be taken. In principal it is possible to remove the complete lesion by continuously removing tissue until no tumor tissue is left. A problem with this is that currently the end point where to stop the VAB is not well defined. Currently VAB is continued until all the calcifications visible under X-ray are removed. Recent investigations have shown however that this is not a reliable way of defining the end point in removing the tumor [S. Penco, S. Rizzo, A. C. Bozzini, A. Latronico, S. Menna, E. Cassano, M. Bellomi, “Stereotactic vacuum-assisted breast biopsy is not a therapeutic procedure even when all mammographically found calcifications are removed: analysis of 4,086 procedures”, AJR 195 (2010) pp. 1255-1260]. If the VAB had a well defined end point it would have the potential to replace the widely used lumpectomy procedure (open surgery) to remove the tumor with a single needle insertion procedure. This would imply less patient trauma and significantly reducing the cost of the procedure.
In case of tissue ablation, such as isothermal ablation of cancer tumors, a physician inserts the ablation needle to a proper position for treatment, however often an additional device is required, e.g. a scanning device, to guide the physician to the desired position. Further, the physician has no tissue feedback of progress as to how far the ablation zone has reached, and therefore the end point for the procedure is not well defined.